Device for circular grinding, sanding and stripping tools to attach to any power drive

ABSTRACT

A mounting arrangement for allowing a variety of circular grinding, sanding or stripping devices to attach to the same power source having a spindle drive shaft. The devices are substantially enclosed by a rigid guard housing and adjustment means are provided to change the angle of the housing with respect to the drive shaft, thereby changing the amount of exposure of the devices to the work surface. The rigid housing is mounted at a fixed axial position on the shaft and is free to rotate relative to the drive shaft. A mounting shaft is attached to the drive shaft on one end thereof and to a resurfacing device on its other end. A bearing allows the mounting shaft to rotate relative to the housing. A support plate is attached to the housing and to the drive shaft.

BACKGROUND AND OBJECT OF THE INVENTION

There are many power sanding, grinding and stripping tools used forremoving paint and other coatings from wood, fiberglass, steel, andresin surfaces. These tools are designed with cutting head and motordrive as a single unit. The present invention is designed to mount anyone of these various cutting tool onto the same power source.

The present invention allows the purchase of one power drive or sourceand allows the purchase of multiple tool accessories that will mount onthat power drive.

In the invention presented herein, stripping is accomplished by a barstyle blade holder having stripping elements capable of stripping twoadjacent 90 degree surfaces simultaneously. This is analogous to thestripping action described in the copending patent application Ser. No.10/671920 in the names of the same inventors named herein. This toolrequires a special type of rigid guard housing that also doubles as adust collector. Because of the specialized type of guard housing, it isnecessary to be able to remove the cutting action of the tool with theguard housing and the invention allows the user the ability to do so.

There are many rotary-resurfacing tools on the market. All of these arepermanently mounted and are unable to be interchanged with spindle typepower drives. All of these tools could be interchangeable with spindletype power drives with this invention. One advantage of this device isthat since the tool head is not fixed to the body of the motor, it canmove in relation to the power drive. Thus, for some applications, theoperator can adjust the position of the head and motor body to fit intotight places.

There are many prior art rotary-resurfacing tools on the market, butthey are cumbersome to handle and are unable to clean coatings fromareas next to windows, doorframes, and corner boards. Some examples arediscussed below.

U.S. Pat. No. 4,544,957, issued to Zayat, describes a rotary resurfacingtool capable of simultaneously resurfacing two surfaces with a rotarydisc. The tool is designed to simultaneously to remove a coating fromthe horizontal surface of a clapboard and the underside butt end of theadjacent clapboard. The mounting assembly for the rotary disk ispermanently attached to a power drive.

U.S. Pat. No. 5,609,516, issued to Courson, describes a power tool withabrasive sheets enclosed by a circular shroud covering. The shroudcovers the abrasive sheets allowing the collection of dust by a vacuumsystem. While it appears that this device can be mounted on a spindleshaft, it must be noted that the device does not need a housing toadjust the depth of a cutting edge.

U.S. Pat. No. 5,791,979 describes a vacuum shroud covering a grindingtool. The flexible bonnet surrounding the grinding disc allows for thecollection of stripped debris into a vacuum. While the drive shaft ismounted to the motor by means of a chuck, the flexible bonnet isattached to the motor drive by four machine screws, which do not allowfor easy removal.

U.S. Pat. No. 6,027,399, issued to Stewart, describes a grinding toolaccessory shroud for containing and removing dust into a vacuum. Thegrinding tool accessory has flexible bristles with two chambers, theinner chamber collects the dust and the outer chamber flexes forcontoured portions of a work surface. The arrangement of this tool islike that of Duncan, where a chuck attaches to the drive shaft and thebonnet is attached by machine screws to the motor drive.

U.S. Pat. No. 4,765,099, issued to Tanner, describes a sanding and dustcollecting apparatus that consists of a flexible curtain for containmentof dust around a sanding disc. The curtain is hard mounted to the powerdrive.

U.S. Pat. No. 6,148,880, issued to Dehde et al., describes a flatsurface-milling machine with two or more cutters, but no removal systemis provided and the machine only grinds one surface at a time. This alsois a permanently mounted system and is not suited to an adapter of thetype disclosed herein.

U.S. Pat. Nos. 4,337,811; 3,731,338; and 6,190,099, issued toPartington, Walsh and Schultze, respectively, all describe circularrotary planers or grinders with no ability to simultaneously grind twosurfaces and no dust removal system. All these systems are permanentlymounted.

U.S. Pat. No. 6,491,575, issued to Sarantits, describes a rotary toolwith replaceable blades that can resurface two surfaces simultaneously,a semi rigid guard and a dust collecting system. The cutting depth ofthe horizontal work surface is set by ball bearings and the dustcollection system is a shroud surrounding the entire work surface. Thesemi rigid guard is permanently mounted to the power drive.

U.S. Pat. No. 5,520,076, issued to Junkers, describes a threadedconnector for a power tool having a threaded spindle. The arrangementincludes a one piece metal device with a female threaded connector endand a hexagonal socket end. It does not allow for the depth controlneeded for a power cutting, grinding or sanding tool.

U.S. Pat. No. 5,586,847, issued to Mattern, describes a power tooladapter for a motorized screw driver. A metal sleeve that fits over thehexagonal screw driver bit holds a drill bit. This allows for the drillbit to be easily removed. An operator can pre-drill starter holes forscrews and easily remove the drill bit, exposing the screw driver headfor inserting screws.

BRIEF SUMMARY OF THE INVENTION

The invention is generally directed to resurfacing tools having variouscircular sanding, grinding and stripping devices adapted to be coupledto a drive shaft and that require the use of a rigid guard housing forprotection of the operator of the tool. A mounting assembly is providedto support the housing from the drive shaft a fixed distance from theresurfacing devices while allowing the drive shaft to rotate freelyrelative to the housing. Concurrently, the resurfacing devices arerotated by the drive shaft. The above is accomplished in part by amounting shaft having one end attached to the drive shaft and the otherend attached to the resurfacing devices and a bearing for permitting themounting shaft to rotate freely with respect to the housing. Themounting arrangement also includes adjusting means to change the angleof the housing relative to the axis of the drive shaft so that theexposure of the resurfacing elements to the work surface is adjustable.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings show the best mode of the invention as presentlycontemplated wherein:

FIG. 1A is an axial view of the threaded mounting shaft;

FIG. 1B is a cross sectional view of the mounting shaft along the lines1B in FIG. 1A;

FIG. 2 is an exploded side elevation view of the mounting assembly ofthe invention;

FIG. 3A is a side elevation view similar to FIG. 2 with the blade holderomitted; and

FIG. 3A is a bottom view of the assembled resurfacing tool showingdetails of the blade holder.

DETAILED DESCRIPTION OF THE INVENTION

As best seen in FIGS. 2-4, the paint/coating stripping tool 2 of theinvention is seen to comprise a power unit 40 which drives a drive shaft50. The drive shaft 50 is intended to be coupled to a bar style holder24 which has mounted thereon two cutting blades 26 held in place by twoblade screws 16, FIGS. 2 and 3A,

A mounting shaft 8 attaches to the threaded shaft 5 on one end 8 a andto the blade holder 24 on the other end 8 c. The shaft 8 has a tappedthreaded cylindrical opening starting near the end 8 a of the mountingshaft and continuing nearly the entire length thereof, this threadedopening receiving the threaded drive shaft 50. The other end 8 c of theshaft 8 is closed by an end wall 8 f and has a notch or channel 8 d(seen best in FIGS. 1B, 3 and 3A) formed therein for receiving the bladeholder 24. The end 8 c is also provided with tapped holes 8 e forreceiving screws 16 to hold the blade holder securely in notch 8 d.

A rigid guard/dust collector 22 is attached to a bearing block 12 withtwo rigid dust collector screws 18 which maintain a set distance betweenthe rigid guard/dust collector 22 and the bearing block 12 with tworigid dust collector spacers 28 through which the rigid dust collectorscrews 18 pass. The rigid guard/dust collector 22 is used to adjust theexposure of the cutting blades 26 to the work surface. This adjustmentis made by the face cutting screw 34 and lock nut 34A. The angle of therigid guard/dust collector to the cutting blades is changed by rotatingthe face cutting screw 34 which moves the rigid guard/dust collector 22up and down relative to the bearing block 12 with the pivot point at animaginary line between the two dust collector screws 18. A screw 32,FIGS. 2-4, is mounted on the housing 22 and extends generallyperpendicular to the drive shaft 50.

FIG. 3 shows the exploded view of the best mode of the tool 2 of theinvention including a bar style holder which operates as the resurfacingand stripping device portion of the tool. The mounting shaft 8 extendsthrough the rigid guard/dust collector 22 through two bearing rings 13,is seated in the bearing block 12 and is secured in this position withthe snap ring 10 around the threaded mounting shaft indent 8 b.

The bearing block 12 serves as an attachment point for the handleassembly consisting of the handle grip 4, the handle extension 6 andhandle screw 20. The rigid guard/dust collector 22 is attached to thebearing block with two rigid dust collector screws 18 and two rigid dustcollector spacers 28. The rigid guard/dust collector 22 also is theattachment port for the hose connector 37.

The threaded mounting shaft 8 has these distinct features: an indentspace 8 b for attaching the snap ring 10 and the threaded end 8 a (seeFIG. 1B for 8 a) for attaching to the drive shaft 50 of the powersource. FIG. 2 shows the adapter end 8 c where the mounting shaftattaches to a bar style blade holder 24 of the paint/coating strippingdevice 2. The blade holder 24 is attached to the mounting shaft 8 bymeans of two screws 16, FIG. 2, and has two cutting blades 26 held inplace with two blade screws 14.

1. (canceled)
 2. A tool for resurfacing a work surface comprising: adrive shaft; a holder for mounting resurfacing elements facing the worksurface, said holder extending generally perpendicular to the axis ofthe drive shaft; a rigid housing substantially enclosing the holder onall sides except for the sides exposing said resurfacing elements tosaid work surface; and means for mounting the housing at a fixed axialposition along the drive shaft and spaced from said holder whileconcurrently permitting the drive shaft to rotate freely with respect tothe housing, said means comprising a mounting shaft having one endformed for attachment to the drive shaft and an opposite end formed forattachment to the holder, and bearings for permitting said mountingshaft to rotate freely with respect to said housing.
 3. The tool ofclaim 2 further including adjusting means for changing the angle of thehousing relative to the axis of the drive shaft whereby the exposure ofthe resurfacing elements to the work surface is adjusted.
 4. The tool ofclaim 3 wherein said adjusting means includes a bearing plate fixed tosaid housing and an adjusting screw rotatable to move the housing towardor away from the bearing plate.
 5. The tool of claim 4 wherein thebearing is seated in the plate and is secured in position by a snap ringcarried in an annular indent in the mounting shaft.
 6. The tool of claim2 wherein the housing includes an opening adapted for connection to avacuum source.
 7. The tool of claim further including a handle assemblyconnected to the plate for manually grasping the tool.